Convertible circular bench saw and mitering saw

ABSTRACT

A convertible saw with a circular saw blade which is of a very simple design so as to permit the plate-shaped worktable with the elements thereon including the motor and saw blade to be reversed 180* from an upper position in which miter cuts may be made to a lower position in which long straight cuts may be made. In the upper mitering position the motor and saw blade may be pivoted downwardly toward the worktable to cut through a workpiece, while in the lower position the motor and saw blade are locked to the worktable so that the saw blade projects for a considerable distance through the slot in the worktable.

United States Patent CONVERTIBLE CIRCULAR BENCH SAW AND MITERING SAW 17Claims, 6 Drawing Figs.

US. Cl. 143/1, 143/6, 143/46 Int. Cl B27b 5/00 Field of Search 143/6, 1,46, 47; 83/(lnquired) Primary ExaminerDonald R. Schran Attorney-Craig,Antonelli, Stewart & Hill ABSTRACT: A convertible saw with a circularsaw blade which is of a very simple design so as to permit theplateshaped worktable with the elements thereon including the motor andsaw blade to be reversed 180 from an upper position in which miter cutsmay be made to a lower position in which long straight cuts may be made.In the upper mitering position the motor and saw blade may be pivoteddownwardly toward the worktable to cut through a workpiece, while in thelower position the motor and saw blade are locked to the worktable sothat the saw blade projects for a considerable distance through the slotin the worktable.

Patented March 16, 1971 3,570,564

3 Sheets-Sheet 1 INVENTOR 077'0 BERGLER BY 6w; 2W-

ATTORNEYS Patented March 16, 1971 3,570,564

3 Sheets-Sheet 2 INVENTOR ATTORNEYS Patented March 16, 1911 3,570,564

5 Sheets-Sheet 3 INVENTOR BY 6a; A W- ATTORNEYS CONVERTIBLE CIRCULARBENQH fiAW AND MITERWG SAW The present invention relates to aconvertible .machine which forms the combination of a bench saw and amitering saw and comprises a single motor-driven circular saw blade andworkpiece supporting and guiding means for the two different purposes ofthe machine.

Such convertible machines which may be employed either as a circularbench saw or as a mitering saw are generally known. They have beendesigned to satisfy the need for a multiple purpose machine whicheliminates the expense as well as the space required for severalindividual machines each of which is built for only one purpose. Theseknown convertible bench and mitering saws have, however, thedisadvantage that their convertibility and the different requirementswhich they have to fulfill require them to be rather heavy, large andexpensive.

Thus, for example, there are convertible saws of this type known inwhich the saw blade projects upwardly through a slot in the worktablewhen the machine is used either as a normal bench saw for long straightcuts or for carrying out miter cuts. Such saws have the disadvantagethat, when making miter cuts, the workpieces are not pressed by thecutting pressure against the worktable and the miter guide or stop barso that special clamping means are required. These saws are thereforenot suitable for mitering small strips or workpieces of a specialcross-sectional shape or such work can at least not be carried outeconomically.

For employing a mitering saw also as a bench saw, it is also known tomount the work plate of a bench saw as an additional element on thepivotable saw housing of the mitering saw. This additional work platemay, however, only be relatively small because it obstructs the viewupon the cut when the saw is used for mitering work. Moreover, such asaw is hard to manipulate since the second work plate which is mountedon the pivotable saw housing increases considerably the weight of thishousing. The conversion of this machine from straight bench saw cuttingto miter cutting is also rather complicated. Finally, the pivotablehoodlike guard which is required on such a saw for safety reasons mustbe of a telescoping construction since the second work plate which isprovided on the upper side of the saw housing limits the movability ofthis guard.

The most important objects of the present are to provide a convertiblebench and mitering saw which does not possess any of the above-mentioneddisadvantages of such saws as heretofore used, is inexpensive and easyto transport and to manipulate, may be easily and quickly converted fromone use to another, and is in its entirety of a weight so as to permit asingle person to carry it when it is to be used, for example, in theinterior construction of rooms in which boards or strips have to be cutalternately to certain lengths or to form miter joints.

The essential features of the invention for attaining these objectsconsist in providing the machine with a work plate, in providing a partof this work plate with a straight slot for the entry of the circularsaw blade, in pivotably mounting the saw blade and its bearing means onone side of the work plate so as to be pivotable relative to this platefor carrying out miter cuts, and in mounting the work plate so as to bereversible together with the saw blade and its bearing means about anangle of 180 from a first position in which the axis of rotation of thesaw blade is located above the work plate for carrying out miter cuts toa second position in which the axis of the saw blade is locatedunderneath the work plate as in a normal circular bench saw for carryingout long straight cuts.

Another feature of the invention consists in providing simple adjustablelocking means which, when the saw blade in the first or miter-cuttingposition has been pivoted toward the work plate and the saw blade haspassed into the slot in this plate, will lock the saw blade to the workplate in a position in which, when the work plate together with the sawblade is then reversed to the second position, the saw blade willproject upwardly through the slot in the work plate for the distancerequired for a straight-cutting operation.

For pivotably mounting the saw blade and its bearing means on the workplate for miter-cutting operations the invention further provides ahousing for the saw blade in which the saw blade is rotatably mountedand which, in turn, is pivotably mounted in the work plate. The motorfor driving the saw blade is preferably mounted directly on this sawhousing and the side of the motor and of this housing facing the workplate is designed so as to permit the saw blade when in the positionunderneath the work plate to project as far as possible through the slotin the work plate. Since on the first or miter-cutting side of the workplate a guide bar is provided for guiding the workpiece at the desiredangle to the saw blade for carrying out a miter cut, the saw housing isprovided with a suitable recess in its lower side which permits thehousing with the saw blade to be pivoted over the guide bar to itslowest position relative to the worktable.

For adjusting the saw blade and the guide bar at different angles toeach other, the invention provides the guide bar to be rigidly mountedon the miter-cutting side of the work plate and the saw housing whichcarries the saw blade and its driving motor to be mounted on the workplate to permit it to be turned to different angles about an axis whichextends perpendicular to the work plate.

For this purpose, the invention further provides the work plate to bedivided into two parts, namely, the work plate itself and a circulardisc which is rotatably mounted in a circular aperture in the work plateand provided with the slot through which the saw blade may projectduring either of its cutting operations. Since the saw housing ispivotably mounted on the circular disc about an axis which extendsparallel to the plane of this plate, the saw blade is at all times inalignment with the slot in this disc and may be adjusted to any anglerelative to the miter guide bar and be clamped by simple means in theadjusted position to the work plate.

As already indicated, it is another object of the invention to make thenew machine of the smallest possible size and the lightest possibleweight. For attaining this object, the invention provides that thecircular disc which is rotatable'in'the work plate and serves foradjusting the saw blade to the desired angle relative to the guide barfor miter cuts is made of the smallest possible diameter which, in turn,permits the work plate'in which this circular disc is rotatably mountedto be made of a relatively small size. For reducing the diameter of thecircular disc as much as possible, the invention takes ad vantage of thefact that for miter-cutting operations, in which the saw blade ispivoted so as to cut downwardly through the workpiece the saw blade onlyneeds to project sufficiently through the slot in the circular disc soas to sever the workpiece. Consequently, for miter-cutting operationsthe slot does not have to be as long as it would have to be when thework plate together with the circular disc, the saw housing and the sawblade is turned over about an angle of to its other position for longstraight cuts, in which the saw blade should pass upwardly through theslot so as toproject to the greatest possible height above the upperside of the work plate and the circular disc since this heightdetermines the maximum height or thickness of the workpieces to be cut.Consequently, for these cutting operations the slot should have a lengthalmost as large as or larger than the diameter of the circular sawblade.

Since for these straight cutting operations the circular disc is clampedin a fixed position to the work plate in which the plane of the sawblade and the slot in the circular disc extend parallel to the guide barfor guiding the workpiece in a straight direction, the inventionprovides that this slot be extended through the outer periphery of thecircular disc and for the desired length into the work plate itself.

While for miter-cutting operations the saw blade is guarded by the sawhousing, safety regulations require the circular saw blade especially ofa bench saw to be provided with a suitable curved guard which is usuallydesigned so as also to serve as a splitting wedge which, when a largercut is being made into a workpiece, passes into the cut and slightlywedges apart its sidewalls so as to facilitate the cutting operation andprevent excessive friction of the saw blade on the sidewalls of the cut.Since this splitting wedge should be effective immediately above theupper surface of the work plate in its second or straight-cuttingposition, the invention provides the mentioned slot in the work platewhich forms a straight extension of the slot in the circular disc to befurther extended and the splitting wedge to be removably secured to thesaw housing which is then located underneath the work plate. Thesplitting wedge then extends through the last part of this slot to theupper side of the work plate and around a part of the periphery of thecutting edge of the saw blade.

Although for mounting the work plate with the various elements thereoneither in the first or miter-cutting position or in the reversed secondposition for carrying out large cuts, various means may be provided, forexample, in the form of feet which may be connected to either side ofthe work plate, or may be pivoted so as to project from one side or theother, it is more advantageous to combine the various elements of themachine into a structural unit by pivotably mounting the work plate in alight supporting frame so as to permit it to be easily pivoted in thisframe from the first to the second position and vice versa and to belocked in either of these position. Since the reversal of thework-supporting sides of the work plate within the supporting frame doesnot change the cutting direction of the saw blade, the operator of themachine may remain in the same position in front of the supporting frameto carry out either of the cutting operation. The supporting frame maytherefore even be secured in a fixed position on a bench, table or thelike.

The machine according to the invention has the further advantage that itmay be provided with removable supporting rails or the like on which anadditional work plate is slidable in the axial direction of the sawblade and may be locked thereon at the desired distance from the sawblade when the machine is employed as a bench saw. The main work plateof the machine may in this manner be enlarged as may be required in aparticular case. If such supporting rails were already mounted on themachine for a previous miter-cutting operation, for example, forsupporting a work-guiding bar, stop member or the like, these supportingrails may be left on the machine when the main work table is reversedfor straightcutting operations and may then be employed for mounting theadditional work plate thereon.

The above mentioned as well as additional features and advantages of thepresent invention will become further apparent from the followingdetailed description thereof, which is to be read with reference to theaccompanying drawings, in which:

FIG. 1 shows a side view of the convertible machine according to theinvention in its position for being used as a mitercutting saw;

FIG. 2 shows a top view of the machine in the position according to FIG.1

FIG. 3 shows a side view of the machine according to FIG. 1, but in itsposition for being used as a normal circular or bench saw;

FIG. 4 shows a top view of the machine in the position according to FIG.3;

FIG. 5 shows a perspective view of a part of the machine in its positionas a bench saw and of an additional adjustable work plate mountedthereon; while FIG. 6 shows a cross section of the additional work platewhich is taken in a direction transverse to the supporting bars whichare mounted on the machine frame, and also illustrates a longitudinalguide bar which may be mounted on the main work plate according to FIGS.3 and 4 or on the additional work plate according to FIG. 5.

As illustrated particularly in FIGS. 1 and 2 of the drawings, theconvertible machine according tothe invention forming a circular benchsaw and a miter-cutting saw, comprises a main frame 11 in which a workplate 2 is mounted so as to be pivotable about pivot pins 3 in thedirection of the arrow 4 to the position as shown in FIG. 3. Forsecuring the work plate 2 together with the various elements thereonrelative to the frame 1 in the position asshown in FIG. 1, a lockingbolt 5 is provided in frame 1 which then engages into a correspondingbore in a bracket 6 on work plate 2. When work plate 2 together with theelements thereon is pivoted about the pivot springs 3 at an angle of 180to the position as shown in FIG. 3, it may also be locked in thisposition by inserting the locking bolt 5 into the bore in the otherbracket 7 on work plate 2.

Work plate 2 carries a transverse stop or guide bar 8 which in thisembodiment of the invention is mounted on a supporting element 9, theends 9a and 9b of which together with the ends of stop bar 8 contain thepivot pins 3 which support the work plate 2 in the frame l. Thesupporting element 9 of guide bar 8 is mounted by means of screws (notshown) on work plate 2. Guide bar 8 and supporting element 9 also serveas means for guiding and holding down a rotatable circular disc 11 whichis inserted into a circular aperture in work plate 2 and has integrallythereon a bushing 12 in which by means of a pin 113 the saw housing 16together with the motor 15 and the saw blade 14 is mounted so as to bepivotable about the axis 13a in the directions of the double arrow 17. Adraw spring 18 which is connected at one end to a projection on thebearing member 12 tends to draw the saw housing 16 at all times in theupward direction. For varying its effective strength, spring 18 may beconnected to an arm 29 which is adjustably secured to bearing member 12.The other end of spring 18 may be directly connected to the circulardisc 11. The lower side 10a and 10b of the saw housing 16 is flattenedso that for making a miter cut on a workpiece 21, as indicated indot-and-dash lines in FIG. 1, only a relatively small saw blade 14 willbe required, while when the machine is to be used as a bench saw asshown in FIG. 3, saw blade 14 will project sufficiently from belowthrough the slot 27 to cut a relatively high or thick workpiece. Thepart 20a of the saw housing forms for this purpose a tangent on thesmallest possible diameter of motor 115. This tangent and a straightline connecting the axis of rotation of saw blade 14 with the pivot axis13a together enclose an angle which corresponds to the adjusting angle aof the saw housing 16 relative to the work plate 2. The inclined surface20b of saw housing 16 is similarly designed for the operation of themachine as a bench saw. The saw housing 16 is further provided with arecess 16a into which, when the housing is pivoted downwardly the guidebar 8 and its supporting element 9 may pass without interference. Thesaw housing 16 is provided with a handlebar 22 by means of which the sawblade 14 which rotates in the direction of the arrow 23 may be loweredso as to cut the workpiece 21 which abuts against the guide bar 8. Forlimiting the extent of the pivoting movement of saw housing 16, thelatter is provided with a stop member 16b which in the position as shownin-FIG. 2 abuts against the guide bar 8, while when the machine is to beemployed as a bench saw, this stop member 16b may be pivoted to theposition as indicated in FIG. 2 in dotted lines.

Before being used as a miter-cutting saw, the circular disc ll 1together with the saw housing 16, carrying the saw blade l4 and itsmotor 15 must be turned in work plate 2 in the direction of the arrows24 (FIG. 2) so that the saw blade 14 will be disposed at the desiredangle to the guide bar 8. After the saw blade has been properlyadjusted, disc i1 is to be clamped together with work plate 2 by meansof a double claw 25 which is secured by a pair of screws to work plate 2and is pressed upwardly by a hand screw 26 on its right end whereby itsleft end is pressed against the circular disc 11. Disc ill is providedwith a slot 27 into which the saw blade 14 may enter when loweredsufficiently to cut through the workpiece 21. For reinforcing the thinwork plate 2 which consists of sheet metal, corrugations 2% areimpressed therein from below which extend at right angles to theupwardly bent front and rear edges 29 of work plate 2 which likewiseserve for reinforcing this plate. As may be seen in FIG. 1, the uppersurfaces of these corrugations 28 also serve as supporting surfaces forthe workpiece 21 when carrying out miter cuts.

Work plate 2 is further provided with a guide rail 30 which is screwedthereon by means of straps 3B but is not actually used until work plate2 with the various elements thereon has been pivoted to the positionaccording to FIGS. 3 and 4 in which the machine serves as a circularbench saw. Before work plate 2 is thus turned over it is, however,necessary to insert a stop bolt 32 into its bearing recess 33 in housingto. This stop bolt subsequently serves for securing the saw blade 14 inslot 27 at the desired level relative to work plate 2. in order topermit the saw blade 14 to project as far as possible from below throughthe slot 27 without requiring the circular disc 11 to be made of a verylarge diameter, work plate 2 is provided with a slot 27a which, whendisc 11 is in its basic position as shown particularly in FIG. 4, formsa straight extension of the slot 27 in disc 11. This slot 270 in workplate 2 is, however, of importance only when the machine is used as abench saw since for miter-cutting operations when the machine is in theposition as shown in FIGS. 1 and 2 the saw blade 14 only needs to enterfor a short distance into the slot 27 when cutting through a workpiece21.

In FIGS. 3 and 4, work plate 2 with the various elements thereonincluding the motor 15, the saw blade 14, and the housing 16 is pivotedat an angle of 180 from the position according to FIGS. 1 and 2 in whichit is locked by means of the locking bolt 5 which is then inserted intothe bore in bracket 7. in addition, base plate 2 is secured in thisposition by the weight of saw blade 14, motor 15, and saw housing 16 andby the action of spring 18 which tend to turn the saw housing in thecounterclockwise direction about the pivot pins 3 and thereby press thebearing part 33 upwardly against the stop bolt 32. This stop bolt 32consists of a screw part 34 which is screwed into a threaded tubularpart 36 the closed end of which is connected by a universal joint tobase plate 2 so as to permit this part 36 to be turned by a handwheel 35relative to the screw part 34 to vary the effective length of stop bolt32 and thus to vary the distance which the saw blade 14 projects abovethe work plate 2 when the machine is used as a bench saw and work plate2 together with the circular disc 11 support the workpiece to be cut.FIG. 3 shows the bench saw when adjusted to the greatest cuttingthickness in which the flat part b which now forms the upper side of sawhousing 16 abuts against the corrugations 28 on work plate 2. Since thedirection of rotation of motor 15 remain the same in its upper and lowerpositions, saw blade 14 always rotates in the direction of the arrow 23.The operator's stand is therefore located at the right side of themachine when it is used as a mitering saw according to H6. l and alsowhen used as a bench saw according to FiG. 3.

Since the machine when used as a circular bench saw has to comply withspecial safely regulations, a blade guard which also serves as asplitting wedge 37 is provided around the saw blade 14. The rear end ofthis splitting wedge 37 extends through the rear end of slot 27a in workplate 2 and is secured to a bracket 38 on the saw housing 16. Aspreviously mentioned, slot 2% forms an extension of slot 27 in thecircular disc ll so that even though the latter has a relatively smalldiameter, the large saw blade 1 may project so far above the work plate2 as to permit workpieces of a considerably height or thickness to becut. Slot 27a therefore has two functions, namely, to permit thesplitting wedge 37 to be secured in a simple manner and to extend thelength of the slot 27 in the circular disc ll.

FIGS. 3 and 4 further illustrate that, when the machine is used as abench saw, the necessary guide bar 39 may be easily secured to the workplate 2. Another guide bar 40 may also be provided for pushing theworkpiece forwardly while being cut. While this guide bar 46 is slidablealong the guide rail 39 as previously mentioned, guide bar 39 isslidably along and adapted to be clamped in a fixed position to theright bent over edge 29.0f work plate 2 by means of associated guidestrips 41 anda tomrny screw 42.

The present invention therefore provides a very advantageous combinationofa circular bench saw with a mitercutting saw which may be easily andquickly converted from one to the other. After being used as a bench sawin the position as shown in FIG. 3 and d, it is merely necessary toremove the splitting wedge 37 and to retract the locking bolt 5 from thebore in bracket 7 before the base plate 2 and all the elements thereonmay be swung over to the mitering position according to FIGS. 1 and 2.When the machine is then to be used as a mitering saw, it is onlynecessary to unhook the stop bolt 32 from its bearing part 33 on the sawhousing H6.

H6. 5 illustrates an auxiliary worktable according to the inventionwhich consists of a plate 49 of thin sheet metal which may, if desired,be provided with reinforcing corrugations similarly as shown on the workplate 2 in FIG. 2. For supporting this auxiliary work plate 49 the endwall of frame 1 is provided with bores 43 into which the left ends of apair of sup.- porting rods 44 are inserted and clamped by setscrews 43,while their right ends are supported by a stand 45 which may be adjustedin height on its post 47 .and then be clamped thereon by a setscrew 46.The downwardly bent front edge 50 of plate 49 is exactly in alignmentwith the corresponding front edge 29 of work plate 2. Since the edges 29and 50 are exactly alike, a longitudinal guide bar as illustrated, forexample, in FIG. 6 at 31 may be mounted either on work plate 2 or on theauxiliary plate 49. if plate 49 is adjusted to a position in which itdirectly abuts against the work plate 2, the longitu dinal guide bar 51may also be shifted from one to the other.

For sliding the auxiliary work plate 49 in the axial direction of sawblade 14, and thus also in the axial direction of pivot pins 3 along thesupporting rods 44, plate 49 is provided on its lower side with slidemembers 52 each of which may have, for example a triangular or roundlower side resting on the respective rod 84. These slide members 52 maybe locked on rods 44 by clamping screws 53. As may be seen in E16. 5,plate 49 may be lifted either toward the right or left to enlarge thesupport ing surface for the workpieces to the desired size.

it will not be necessary in every case toprovide an additional stand asa support for the ends of the supporting rods 44, for example, whenthese rods have a relatively short length. It is also advisable tosupply the machine with several sets of supporting rods of differentlengths so as to permit the work-supporting surface to be enlarged atwill. Thus, for example, if the work plate 2 of the machine has a sizeof only X 80 cm., the supporting surface may be enlarged so as to permitentire doors of a length of more than 2 meters to be worked upon. Themachine is in this case provided with supporting rods 44 of aconsiderable length and the auxiliary work plate 49 is shifted thereonfar toward the right. The fact that a large gap is them formed betweenthe main work plate 2 and the auxiliary plate 49 in which the workpieceis not supported does not affect the sawing operation; on the contrary,this gap may even facilitate the manipulation of the workpiece.

FIG. 6 finally illustrates the simple manner in which the longitudinalguide bar 51 may be secured to the auxiliary work plate 49. The frontend of the guide bar is simple bent downwardly to form a V-shaped clamp54 which may be slipped over the downwardly bent edge 59 of plate 49 andbe tightly clamped thereon by a screw 55 after guide bar 51 has beenshifted to the proper position on plate 49. Of course, other oradditional guide bars or similar elements may also be mounted on theedge 50 of the plate 49 or on the corresponding edge 29 of the main workplate 2.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, lwish to have it understood thatit is in no way limited to the details of such embodiments but iscapable of numerous modifications within the scope of the appendedclaims.

1 claim:

1. A convertible saw adapted to be used in a first position as a mitersaw and in a second position as a circular bench saw comprising: t

a work plate having a part with a straight slot therein and havingopposite first and second sides, said first side being adapted in saidfirst position to face upwardly to support a workpiece thereon formaking miter cuts, said second side adapted in said second position toface upwardly to support a workpiece thereon for making longitudinalcuts;

bearing means for mounting said saw blade so as to be rotatable aboutits axis;

means for driving said saw blade;

means for pivotably connecting said bearing means to said first side ofsaid work plate to permit said saw blade to be pivoted toward said firstside and to .cut from above through said workpiece thereon and then toenter said slot;

means for alternately mounting said workpiece substantially horizontallyin said first position and in said second position;

said bearing means being located above said work plate in said firstposition and below said work plate in said second position; and

releasable locking means for locking said bearings means in said secondposition to said work plate in which the axis of said saw blade isspaced at a fixed small distance from the lower side of said work plateand said saw blade then projects upwardly through said slot and for afixed distance above the upper side of said work plate; wherein saidbearing means comprise a saw housing pivotably connected to said firstside of said work plate, said motor and saw housings having a flattenedside facing said work plate so as to permit said saw housing includingthe driving axis of said motor and saw blade to be pivoted very closelyto said work plate, a guide bar on said first side of said work platefor guiding a workpiece and extending transverse to the normal plane ofsaid saw blade, said housing having a recess in its side facing saidwork plate adjacent to said flattened part, said recess being adapted toreceive said transverse guide bar when said housing is pivoted in saidfirst position to its smallest distance from said work plate.

2. A convertible saw as defined in claim 1, in which said flattened sidehas two parts which are adjacent to each other, one of said flattenedparts forming a tangent on the smallest possible motor diameter, saidtangent together with a straight line intersecting the axis of said sawblade and the pivot axis of said saw housing defining an anglecorresponding to the maximum angle about which said saw housing has tobe pivoted toward said work plate when a workpiece of the greatestadmissible height from said work plate is to be cut in said firstposition, the other flattened part forming a similar tangent whichtogether with said straight line defines the maximum angle which saidsaw housing has to be pivoted toward said work plate for attaining thegreatest possible cutting depth of said saw blade and thus the greatestdistance which said saw blade projects above said work plate in saidsecond position.

3. A convertible saw as defined in claim 1, further comprising a stopmember on said saw housing for limiting the distance to which said sawblade in said first position may be pivoted into said slot, said stopmember being adapted to be moved to an inactive position when said workplate is to be moved from said first position to said second position.

4. A convertible saw as defined in claim 1, in which said work platecomprises two parts, the first of said parts being stationary in saidfirst and second positions and having a circular aperture the secondpart of said work plate forming a circular disc rotatably mounted insaid circular aperture so as to be rotatable about a central axisextending perpendicular to the common plane of said work plate and saiddisc, said disc containing said slot, bearing means for pivotablyconnecting one end of said saw housing to said disc on said first sideof said work plate, said saw housing by being connected to said discbeing adapted in said first position to be turned together with said sawblade to different angles relative to said guide bar for cutting saidworkpiece at different miter angles, means for clamping said disc tosaid stationary part of said work plate when the plane of said saw bladeand said slot extend at a right angle to said guide bar and when saidwork plate including said disc said motor and said saw blade is to bereversed from said first to said second position and when said lockingmeans are in the locking position in which said locking means rigidlyconnect said stationary part of said work plate to said saw housing andin which the axis of said saw blade when in said second position isspaced at said small distance from the lower side of said work plate.

5. A convertible saw as defined in claim 4, in which said slot in saiddisc extends to the periphery of said disc, said stationary part of saidwork plate also having a slot forming a straight extension of said slotin said disc when the plane of said saw blade and said disc slot extendat a right angle to said guide bar so as to permit said saw blade toproject for a greater distance through said work plate in said secondposition than required in said first position.

6. A convertible saw as defined in claim 5, further comprising a curvedguard member also serving as a splitting wedge covering a part of theperipheral surface of said saw blade projecting in said second positionabove said work plate including said disc, the rear end of said guardmember extending downwardly through a part of said extension slot, andmeans for removably securing said end of said guard member to said sawhousing when said housing is in said second position below said workplate.

7. A convertible saw as defined in claim 1, further comprising aconnecting part on said saw housing and another connecting part on saidwork plate, said locking means comprising a spacing element connected insaid second position to said two connecting parts for maintaining saidsaw housing and said work plate at said small distance from each other,said spacing element being removable from at least one of saidconnecting parts when said work plate and the various parts thereon areto be moved from said second position to said first position.

8. A' convertible saw as defined in claim 7, in which said spacingelement comprises an internally threaded tubular member connected at oneend to one of said connecting parts, and a screw member connected at oneend to the other connecting part and screwed into said tubular member,the effective length of said spacing element being adjustable when saidtwo members are turned relative to each other so as to vary the distanceto which said saw blade projects above said work plate in said secondposition. I

9. A convertible saw as defined in claim 1, further comprising a frameand means for pivotably connecting said work plate to said frame topermit said work plate to be pivoted about an angle of from said firstposition to said second position and vice versa.

it). A convertible saw as defined in claim 4, further comprising aframe, and means for pivotably connecting the opposite ends of saidtransverse guide bar to said frame to permit said work plate to bepivoted about an angle of 180 from said first position to said secondposition and vice versa.

11. A convertible saw as defined in claim 10, further comprising meansfor rigidly securing said guide bar to said stationary part of saidfirst side of said work plate, the wall of said circular aperture havingan annular inwardly projecting flange adjacent to said second side ofsaid work plate for supporting said disc in said first position, saidguide bar extending over said disc in said first position so as to holdsaid disc on said flange and to permit it to be rotated between saidflange and said guide bar.

12. A convertible saw as defined in claim 3, in which said work plateconsists of thin sheet metal and has two outer edges parallel to eachother and bent upwardly from said first side of said work plate, saidwork plate having corrugations impressed into said second side andprojecting from said first side and extending at an angle to said edges.

13. A convertible saw as defined in claim 10, further comprisingsupporting bars, means for removably securing said supporting bars tosaid frame so as to extend parallel to the axis of said saw blade, andan auxiliary work plate slidably on said supporting bars in the axialdirection of said saw blade, and means for locking said auxiliary workplate to at least one of said supporting bars.

14. A convertible saw as defined in claim 13, in which said work plateand said auxiliary plate consist of thin sheet metal and each of themhas two outer edges parallel to each other and bent downwardly as seenfrom said second side of said work plate, at least one of said edges ofone of said plates being in straight alignment with the correspondingedge of the other plate and forming a guide rail, and a longitudinalworkguiding bar adapted to be mounted on and slidably along said guiderail and extending parallel to said saw blade on said second side, andmeans for locking said bar in any adjusted position to said guide railof either of said plates.

15. A convertible saw as defined in claim 13, in which one end wall ofsaid frame is provided with bores, said supporting bars forming rodseach having one end adapted to be inserted into one of said bores, meansfor removably securing said rod ends in said bores, and a stand havingarms adapted to connect said rods rigidly to each other near their otherends, if said rods have a considerable length, for supporting said otherends, and means on said stand for adjusting the height of said stand.

16. A convertible saw adapted to be used in a first position as a mitersaw and in second position as a circular bench saw comprising a workplate having a part with a straight slot therein and having oppositefirst and second sides, said first side being adapted in said firstposition to face upwardly to support a workpiece thereon for makingmiter cuts, said second side adapted in said second position to faceupwardly to support a workpiece thereon for making longitudinal cuts,bearing means for mounting said saw blade so as to be rotatable aboutits axis, means for driving said saw blade, means for pivotablyconnecting said bearing means to said first side of said work plate topermit said saw blade to be pivoted toward said first side and to cutfrom above through said workpiece thereon and then to enter said slot,means for alternately mounting said work plate substantiallyhorizontally in said first position and in said second position, saidbearing means being located above said work plate in said first positionand below said work plate in said second position, and releasablelocking means for locking said bearing means in said second position tosaid work plate in which the axis of said saw blade is spaced at a fixedsmall distance from the lower side of said work plate and said saw bladethen projects upwardly through said slot and for a fixed distance abovethe upper side of said work plate, in which said work plate comprisestwo parts, the first of said parts being stationary in said first andsecond positions and having a circular aperture, the second part of saidwork plate forming a circular disc rotatably mounted in said circularaperture so as to be rotatably about a central axis extendingperpendicular to the common plane of said work plate and said disc, saiddisc containing said slot, bearing means comprising a saw housingpivotably connected to said disc on said first side of said work plate,said driving means comprising a motor having a housing directly securedto said saw housing, said saw housing being connected to said disc beingadapted in said first position to be turned together with said saw bladeto different angles relative to a guide bar mounted on said first sideof said work plate for cutting said workpiece at difi'erent miterangles, means for clamping said disc to said stationary part of saidwork plate when the plane of said saw blade and said slot extend at aright angle to said guide bar and when said work plate including saiddisc, said motor and said saw blade is to be reversed from said first tosaid second position and when said locking means are in the lockingposition in which said locking means rigidly connect said stationarypart of said work plate to said saw housing and in which the axis ofsaid saw blade when in said second position is spaced at said smalldistance from the lower side of said work plate.

17. A convertible saw as defined in claim 16, m which said slot and saiddisc extends to the periphery of said disc, said stationary part of saidwork plate also having a slot forming a straight extension of said slotin said disc where the plate of saw blade and said disc slot extend at aright angle to said guide bar so as to permit said saw blade to projectfor a greater distance through said work plate in said second positionthan required in said first position.

1. A convertible saw adapted to be used in a first position as a mitersaw and in a second position as a circular bench saw comprising: a workplate having a part with a straight slot therein and having oppositefirst and second sides, said first side being adapted in said firstposition to face upwardly to support a workpiece thereon for makingmiter cuts, said second side adapted in said second position to faceupwardly to support a workpiece thereon for making longitudinal cuts;bearing means for mounting said saw blade so as to be rotatable aboutits axis; means for driving said saw blade; means for pivotablyconnecting said bearing means to said first side of said work plate topermit said saw blade to be pivoted toward said first side and to cutfrom above through said workpiece thereon and then to enter said slot;means for alternately mounting said workpiece substantially horizontallyin said first position and in said second position; said bearing meansbeing located above said work plate in said first position and belowsaid work plate in said second position; and releasable locking meansfor locking said bearings means in said secOnd position to said workplate in which the axis of said saw blade is spaced at a fixed smalldistance from the lower side of said work plate and said saw blade thenprojects upwardly through said slot and for a fixed distance above theupper side of said work plate; wherein said bearing means comprise a sawhousing pivotably connected to said first side of said work plate, saidmotor and saw housings having a flattened side facing said work plate soas to permit said saw housing including the driving axis of said motorand saw blade to be pivoted very closely to said work plate, a guide baron said first side of said work plate for guiding a workpiece andextending transverse to the normal plane of said saw blade, said housinghaving a recess in its side facing said work plate adjacent to saidflattened part, said recess being adapted to receive said transverseguide bar when said housing is pivoted in said first position to itssmallest distance from said work plate.
 2. A convertible saw as definedin claim 1, in which said flattened side has two parts which areadjacent to each other, one of said flattened parts forming a tangent onthe smallest possible motor diameter, said tangent together with astraight line intersecting the axis of said saw blade and the pivot axisof said saw housing defining an angle corresponding to the maximum angleabout which said saw housing has to be pivoted toward said work platewhen a workpiece of the greatest admissible height from said work plateis to be cut in said first position, the other flattened part forming asimilar tangent which together with said straight line defines themaximum angle which said saw housing has to be pivoted toward said workplate for attaining the greatest possible cutting depth of said sawblade and thus the greatest distance which said saw blade projects abovesaid work plate in said second position.
 3. A convertible saw as definedin claim 1, further comprising a stop member on said saw housing forlimiting the distance to which said saw blade in said first position maybe pivoted into said slot, said stop member being adapted to be moved toan inactive position when said work plate is to be moved from said firstposition to said second position.
 4. A convertible saw as defined inclaim 1, in which said work plate comprises two parts, the first of saidparts being stationary in said first and second positions and having acircular aperture the second part of said work plate forming a circulardisc rotatably mounted in said circular aperture so as to be rotatableabout a central axis extending perpendicular to the common plane of saidwork plate and said disc, said disc containing said slot, bearing meansfor pivotably connecting one end of said saw housing to said disc onsaid first side of said work plate, said saw housing by being connectedto said disc being adapted in said first position to be turned togetherwith said saw blade to different angles relative to said guide bar forcutting said workpiece at different miter angles, means for clampingsaid disc to said stationary part of said work plate when the plane ofsaid saw blade and said slot extend at a right angle to said guide barand when said work plate including said disc said motor and said sawblade is to be reversed from said first to said second position and whensaid locking means are in the locking position in which said lockingmeans rigidly connect said stationary part of said work plate to saidsaw housing and in which the axis of said saw blade when in said secondposition is spaced at said small distance from the lower side of saidwork plate.
 5. A convertible saw as defined in claim 4, in which saidslot in said disc extends to the periphery of said disc, said stationarypart of said work plate also having a slot forming a straight extensionof said slot in said disc when the plane of said saw blade and said discslot extend at a right angle to said guide bar so as to permit said sawblade to project for a greatEr distance through said work plate in saidsecond position than required in said first position.
 6. A convertiblesaw as defined in claim 5, further comprising a curved guard member alsoserving as a splitting wedge covering a part of the peripheral surfaceof said saw blade projecting in said second position above said workplate including said disc, the rear end of said guard member extendingdownwardly through a part of said extension slot, and means forremovably securing said end of said guard member to said saw housingwhen said housing is in said second position below said work plate.
 7. Aconvertible saw as defined in claim 1, further comprising a connectingpart on said saw housing and another connecting part on said work plate,said locking means comprising a spacing element connected in said secondposition to said two connecting parts for maintaining said saw housingand said work plate at said small distance from each other, said spacingelement being removable from at least one of said connecting parts whensaid work plate and the various parts thereon are to be moved from saidsecond position to said first position.
 8. A convertible saw as definedin claim 7, in which said spacing element comprises an internallythreaded tubular member connected at one end to one of said connectingparts, and a screw member connected at one end to the other connectingpart and screwed into said tubular member, the effective length of saidspacing element being adjustable when said two members are turnedrelative to each other so as to vary the distance to which said sawblade projects above said work plate in said second position.
 9. Aconvertible saw as defined in claim 1, further comprising a frame andmeans for pivotably connecting said work plate to said frame to permitsaid work plate to be pivoted about an angle of 180* from said firstposition to said second position and vice versa.
 10. A convertible sawas defined in claim 4, further comprising a frame, and means forpivotably connecting the opposite ends of said transverse guide bar tosaid frame to permit said work plate to be pivoted about an angle of180* from said first position to said second position and vice versa.11. A convertible saw as defined in claim 10, further comprising meansfor rigidly securing said guide bar to said stationary part of saidfirst side of said work plate, the wall of said circular aperture havingan annular inwardly projecting flange adjacent to said second side ofsaid work plate for supporting said disc in said first position, saidguide bar extending over said disc in said first position so as to holdsaid disc on said flange and to permit it to be rotated between saidflange and said guide bar.
 12. A convertible saw as defined in claim 1,in which said work plate consists of thin sheet metal and has two outeredges parallel to each other and bent upwardly from said first side ofsaid work plate, said work plate having corrugations impressed into saidsecond side and projecting from said first side and extending at anangle to said edges.
 13. A convertible saw as defined in claim 10,further comprising supporting bars, means for removably securing saidsupporting bars to said frame so as to extend parallel to the axis ofsaid saw blade, and an auxiliary work plate slidably on said supportingbars in the axial direction of said saw blade, and means for lockingsaid auxiliary work plate to at least one of said supporting bars.
 14. Aconvertible saw as defined in claim 13, in which said work plate andsaid auxiliary plate consist of thin sheet metal and each of them hastwo outer edges parallel to each other and bent downwardly as seen fromsaid second side of said work plate, at least one of said edges of oneof said plates being in straight alignment with the corresponding edgeof the other plate and forming a guide rail, and a longitudinalwork-guiding bar adapted to be mounted on and slidably along said guiderail and extending pArallel to said saw blade on said second side, andmeans for locking said bar in any adjusted position to said guide railof either of said plates.
 15. A convertible saw as defined in claim 13,in which one end wall of said frame is provided with bores, saidsupporting bars forming rods each having one end adapted to be insertedinto one of said bores, means for removably securing said rod ends insaid bores, and a stand having arms adapted to connect said rods rigidlyto each other near their other ends, if said rods have a considerablelength, for supporting said other ends, and means on said stand foradjusting the height of said stand.
 16. A convertible saw adapted to beused in a first position as a miter saw and in second position as acircular bench saw comprising a work plate having a part with a straightslot therein and having opposite first and second sides, said first sidebeing adapted in said first position to face upwardly to support aworkpiece thereon for making miter cuts, said second side adapted insaid second position to face upwardly to support a workpiece thereon formaking longitudinal cuts, bearing means for mounting said saw blade soas to be rotatable about its axis, means for driving said saw blade,means for pivotably connecting said bearing means to said first side ofsaid work plate to permit said saw blade to be pivoted toward said firstside and to cut from above through said workpiece thereon and then toenter said slot, means for alternately mounting said work platesubstantially horizontally in said first position and in said secondposition, said bearing means being located above said work plate in saidfirst position and below said work plate in said second position, andreleasable locking means for locking said bearing means in said secondposition to said work plate in which the axis of said saw blade isspaced at a fixed small distance from the lower side of said work plateand said saw blade then projects upwardly through said slot and for afixed distance above the upper side of said work plate, in which saidwork plate comprises two parts, the first of said parts being stationaryin said first and second positions and having a circular aperture, thesecond part of said work plate forming a circular disc rotatably mountedin said circular aperture so as to be rotatably about a central axisextending perpendicular to the common plane of said work plate and saiddisc, said disc containing said slot, bearing means comprising a sawhousing pivotably connected to said disc on said first side of said workplate, said driving means comprising a motor having a housing directlysecured to said saw housing, said saw housing being connected to saiddisc being adapted in said first position to be turned together withsaid saw blade to different angles relative to a guide bar mounted onsaid first side of said work plate for cutting said workpiece atdifferent miter angles, means for clamping said disc to said stationarypart of said work plate when the plane of said saw blade and said slotextend at a right angle to said guide bar and when said work plateincluding said disc, said motor and said saw blade is to be reversedfrom said first to said second position and when said locking means arein the locking position in which said locking means rigidly connect saidstationary part of said work plate to said saw housing and in which theaxis of said saw blade when in said second position is spaced at saidsmall distance from the lower side of said work plate.
 17. A convertiblesaw as defined in claim 16, in which said slot and said disc extends tothe periphery of said disc, said stationary part of said work plate alsohaving a slot forming a straight extension of said slot in said discwhere the plate of saw blade and said disc slot extend at a right angleto said guide bar so as to permit said saw blade to project for agreater distance through said work plate in said second position thanrequired in said first position.